I can only assume from what I have seen in the past is that when a user with Best answer hides their answer it becomes a question with a best answer but no answers to show for. I can only assume that it was the same person who happened to hide all these.

Hm... Ayan might have asked to be banned. And then he (or possibly the mod that banned him?) could have hid his posts for that reason. This might be his way of leaving the site, as one of the earlier versions of his profile said that he had lost interest in Pokemon. Just a theory there, as Ayan hasn't done anything wrong except for his dupe. Which was ages ago. A Mod isn't just going to ban people randomly.

But yeah, I'll ask him if he comes into chat. But if he won't talk about it, I won't make him.